Mobile communications networks are developing towards a higher data transmission rate, a higher resource utilization rate, and a higher network capacity, which imposes higher requirements on future wireless spectrum resources. However, wireless spectrum resources available for mobile communications are limited; therefore, how to implement a high rate and a high capacity by using limited bandwidth resources becomes a focus of industry research. A device-to-device (D2D) communications technology may be applied to a mobile cellular network to increase the resource utilization rate and network capacity.
In the prior art, a decision process for establishing D2D communication between terminals (UE) in a traditional cellular network is specifically as follows: UE1 sends a request for establishing D2D communication between UE1 and UE2 to a base station (BS); the BS checks whether UE1 and UE2 are both attached to the BS; if either UE1 or UE2 is not attached to the BS, the BS directly returns an error and terminates the decision process; and if both UE1 and UE2 are attached to the BS, the BS sends a measurement request to UE1 and UE2 for UE1 and UE2 to perform measurement. It should be noted that, before the measurement, UE1 and UE2 perform corresponding measurement configuration according to configuration information that is for D2D communication measurement and is in the measurement request. UE1 and UE2 return a measurement response message that includes measurement information to the BS. UE1 and UE2 may further return, to the BS by using the measurement response message, information that is obtained by performing measurement on communication quality of a macro cellular network. The BS determines, according to a result of the measurement, whether to agree to establish D2D communication between UE1 and UE2.
However, in the prior art above, information that is about a wireless network environment and is obtained by the BS and the UEs by simple measurement is limited, and blindness of measurement is easily caused by complexity and variability of the wireless network environment itself; as a result, after the BS learns a result of D2D measurement between the UEs, a determining result may be that D2D communication cannot be established between the UEs, which wastes time and network resources (for example, a frequency spectrum, and energy of the BS and the UEs). In addition, the prior art is limited to UEs attached to a same BS and if UE1 and UE2 are attached to different BSs, establishing D2D communication between UE1 and UE2 is not allowed even if UE1 and UE2 belong to a same operator and a distance between UE1 and UE2 is small. For UEs that support multiple radio access technologies, a most appropriate radio access technology for data transmission of D2D communication between the UEs can be determined only after simple measurement is performed on the different radio access technologies and measurement results are compared. This also causes a waste of time, electricity, and resources in the process of establishing a D2D connection.